1. Field of the Invention
This invention relates to vehicle suspensions and, in particular, to a system used for alignment of a vehicle suspension and axle.
2. Disclosure of Related Art
In a conventional vehicle suspension system, a suspension control arm has a first end rigidly connected to an axle of the vehicle and a second end pivotally connected to a bracket descending from the vehicle frame. The second end of the control arm may terminate in a bushing. The bracket generally includes first and second spaced walls that receive the bushing therebetween. A fastener extends through the first wall of the bracket, through the bushing, and through the second wall of the bracket. The fastener may also extend through one or more washers disposed on either side of the bushing between the first and second walls of the bracket. A nut is used to secure the fastener in place relative to the bracket and the control arm pivots about the fastener.
Conventional suspension systems must be aligned in a fore-aft direction to adjust the fore-aft position of the axle relative to the vehicle frame and thereby align the wheels that are supported on the axle. Improper alignment may lead to premature tire wear among other problems. In most conventional suspension systems, alignment is achieved by moving the control arm relative to the bracket descending from the frame. Each of the spaced walls of the bracket generally includes an elongated slot having a major axis that is parallel to the longitudinal direction of the vehicle. The fastener upon which the control arm pivots is moved within these slots to cause corresponding movement in the suspension control arm and axle. In some conventional suspension systems, a weld collar is disposed about the fastener and the position of the collar is adjusted to move the fastener. The collar is then welded to the frame bracket once proper alignment is achieved. These conventional systems are disadvantageous because realignment of the suspension and axle requires removal of the existing welds and the installation of new welds—a process that requires a relatively large amount of time. In other conventional suspension systems, an eccentric cam is disposed about the fastener and the cam is guided by one or more guides on the frame bracket. Rotation of the cam causes displacement of the fastener within the slots of the frame bracket and thereby adjusts the alignment of the suspension and axle. Although these latter systems enable the suspension to be realigned in a relatively short period of time, the systems require additional components and machining of existing suspension components thereby increasing the cost, weight, and complexity of the suspension. These alignment systems may also have a relatively low load capacity that discourages their use with trailers and other high load vehicles.
The inventors herein have recognized a need for a vehicle suspension that will minimize or eliminate one or more of the above-mentioned deficiencies.